diff --git a/src/output.F90 b/src/output.F90
index 4b1b21096a..1ff53f0d01 100644
--- a/src/output.F90
+++ b/src/output.F90
@@ -1461,7 +1461,10 @@ contains
       global_tallies(:) % sum_sq = t_value * global_tallies(:) % sum_sq
 
       ! Adjust combined estimator
-      k_combined(2) = t_value * k_combined(2)
+      if (n_realizations > 3) then
+        t_value = t_percentile(ONE - alpha/TWO, n_realizations - 3)
+        k_combined(2) = t_value * k_combined(2)
+      end if
     end if
 
     ! write global tallies